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From:   Emanuele Giuseppe Esposito <eesposit@redhat.com>
To:     kvm@vger.kernel.org
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Maxim Levitsky <mlevitsk@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        linux-kernel@vger.kernel.org,
        Emanuele Giuseppe Esposito <eesposit@redhat.com>
Subject: [RFC PATCH 2/2] nSVM: use vmcb_ctrl_area_cached instead of vmcb_control_area in svm_nested_state
Date:   Fri, 17 Sep 2021 08:49:56 -0400
Message-Id: <20210917124956.2042052-3-eesposit@redhat.com>
In-Reply-To: <20210917124956.2042052-1-eesposit@redhat.com>
References: <20210917124956.2042052-1-eesposit@redhat.com>
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This requires changing all vmcb_is_intercept(&svm->nested.ctl, ...)
calls with vmcb_is_intercept_cached().

In addition, in svm_get_nested_state() user space expects a
vmcb_control_area struct, so we need to copy back all fields
in a temporary structure to provide to the user space.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 arch/x86/kvm/svm/nested.c | 42 ++++++++++++++++++++++-----------------
 arch/x86/kvm/svm/svm.c    |  4 ++--
 arch/x86/kvm/svm/svm.h    |  8 ++++----
 3 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index d06a95156535..1f8c90cc4fc3 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -58,8 +58,8 @@ static void svm_inject_page_fault_nested(struct kvm_vcpu *vcpu, struct x86_excep
        struct vcpu_svm *svm = to_svm(vcpu);
        WARN_ON(!is_guest_mode(vcpu));
 
-       if (vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_EXCEPTION_OFFSET + PF_VECTOR) &&
-	   !svm->nested.nested_run_pending) {
+	if (vmcb_is_intercept_cached(&svm->nested.ctl, INTERCEPT_EXCEPTION_OFFSET + PF_VECTOR) &&
+	    !svm->nested.nested_run_pending) {
                svm->vmcb->control.exit_code = SVM_EXIT_EXCP_BASE + PF_VECTOR;
                svm->vmcb->control.exit_code_hi = 0;
                svm->vmcb->control.exit_info_1 = fault->error_code;
@@ -121,7 +121,8 @@ static void nested_svm_uninit_mmu_context(struct kvm_vcpu *vcpu)
 
 void recalc_intercepts(struct vcpu_svm *svm)
 {
-	struct vmcb_control_area *c, *h, *g;
+	struct vmcb_control_area *c, *h;
+	struct vmcb_ctrl_area_cached *g;
 	unsigned int i;
 
 	vmcb_mark_dirty(svm->vmcb, VMCB_INTERCEPTS);
@@ -163,7 +164,7 @@ void recalc_intercepts(struct vcpu_svm *svm)
 	vmcb_set_intercept(c, INTERCEPT_VMSAVE);
 }
 
-static void copy_vmcb_control_area(struct vmcb_control_area *dst,
+static void copy_vmcb_control_area(struct vmcb_ctrl_area_cached *dst,
 				   struct vmcb_control_area *from)
 {
 	unsigned int i;
@@ -219,7 +220,7 @@ static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
 	 */
 	int i;
 
-	if (!(vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_MSR_PROT)))
+	if (!(vmcb_is_intercept_cached(&svm->nested.ctl, INTERCEPT_MSR_PROT)))
 		return true;
 
 	for (i = 0; i < MSRPM_OFFSETS; i++) {
@@ -255,9 +256,9 @@ static bool nested_svm_check_bitmap_pa(struct kvm_vcpu *vcpu, u64 pa, u32 size)
 }
 
 static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu,
-				       struct vmcb_control_area *control)
+				       struct vmcb_ctrl_area_cached *control)
 {
-	if (CC(!vmcb_is_intercept(control, INTERCEPT_VMRUN)))
+	if (CC(!vmcb_is_intercept_cached(control, INTERCEPT_VMRUN)))
 		return false;
 
 	if (CC(control->asid == 0))
@@ -971,7 +972,7 @@ static int nested_svm_exit_handled_msr(struct vcpu_svm *svm)
 	u32 offset, msr, value;
 	int write, mask;
 
-	if (!(vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_MSR_PROT)))
+	if (!(vmcb_is_intercept_cached(&svm->nested.ctl, INTERCEPT_MSR_PROT)))
 		return NESTED_EXIT_HOST;
 
 	msr    = svm->vcpu.arch.regs[VCPU_REGS_RCX];
@@ -998,7 +999,7 @@ static int nested_svm_intercept_ioio(struct vcpu_svm *svm)
 	u8 start_bit;
 	u64 gpa;
 
-	if (!(vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_IOIO_PROT)))
+	if (!(vmcb_is_intercept_cached(&svm->nested.ctl, INTERCEPT_IOIO_PROT)))
 		return NESTED_EXIT_HOST;
 
 	port = svm->vmcb->control.exit_info_1 >> 16;
@@ -1029,12 +1030,12 @@ static int nested_svm_intercept(struct vcpu_svm *svm)
 		vmexit = nested_svm_intercept_ioio(svm);
 		break;
 	case SVM_EXIT_READ_CR0 ... SVM_EXIT_WRITE_CR8: {
-		if (vmcb_is_intercept(&svm->nested.ctl, exit_code))
+		if (vmcb_is_intercept_cached(&svm->nested.ctl, exit_code))
 			vmexit = NESTED_EXIT_DONE;
 		break;
 	}
 	case SVM_EXIT_READ_DR0 ... SVM_EXIT_WRITE_DR7: {
-		if (vmcb_is_intercept(&svm->nested.ctl, exit_code))
+		if (vmcb_is_intercept_cached(&svm->nested.ctl, exit_code))
 			vmexit = NESTED_EXIT_DONE;
 		break;
 	}
@@ -1052,7 +1053,7 @@ static int nested_svm_intercept(struct vcpu_svm *svm)
 		break;
 	}
 	default: {
-		if (vmcb_is_intercept(&svm->nested.ctl, exit_code))
+		if (vmcb_is_intercept_cached(&svm->nested.ctl, exit_code))
 			vmexit = NESTED_EXIT_DONE;
 	}
 	}
@@ -1130,7 +1131,7 @@ static void nested_svm_inject_exception_vmexit(struct vcpu_svm *svm)
 
 static inline bool nested_exit_on_init(struct vcpu_svm *svm)
 {
-	return vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_INIT);
+	return vmcb_is_intercept_cached(&svm->nested.ctl, INTERCEPT_INIT);
 }
 
 static int svm_check_nested_events(struct kvm_vcpu *vcpu)
@@ -1261,6 +1262,7 @@ static int svm_get_nested_state(struct kvm_vcpu *vcpu,
 				u32 user_data_size)
 {
 	struct vcpu_svm *svm;
+	struct vmcb_control_area ctl_temp;
 	struct kvm_nested_state kvm_state = {
 		.flags = 0,
 		.format = KVM_STATE_NESTED_FORMAT_SVM,
@@ -1302,7 +1304,8 @@ static int svm_get_nested_state(struct kvm_vcpu *vcpu,
 	 */
 	if (clear_user(user_vmcb, KVM_STATE_NESTED_SVM_VMCB_SIZE))
 		return -EFAULT;
-	if (copy_to_user(&user_vmcb->control, &svm->nested.ctl,
+	copy_vmcb_ctrl_area_cached(&ctl_temp, &svm->nested.ctl);
+	if (copy_to_user(&user_vmcb->control, &ctl_temp,
 			 sizeof(user_vmcb->control)))
 		return -EFAULT;
 	if (copy_to_user(&user_vmcb->save, &svm->vmcb01.ptr->save,
@@ -1373,8 +1376,9 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
 		goto out_free;
 
 	ret = -EINVAL;
-	if (!nested_vmcb_check_controls(vcpu, ctl))
-		goto out_free;
+	nested_load_control_from_vmcb12(svm, ctl);
+	if (!nested_vmcb_check_controls(vcpu, &svm->nested.ctl))
+		goto out_free_ctl;
 
 	/*
 	 * Processor state contains L2 state.  Check that it is
@@ -1382,7 +1386,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
 	 */
 	cr0 = kvm_read_cr0(vcpu);
         if (((cr0 & X86_CR0_CD) == 0) && (cr0 & X86_CR0_NW))
-		goto out_free;
+		goto out_free_ctl;
 
 	/*
 	 * Validate host state saved from before VMRUN (see
@@ -1428,7 +1432,6 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
 	svm->nested.vmcb12_gpa = kvm_state->hdr.svm.vmcb_pa;
 
 	svm_copy_vmrun_state(&svm->vmcb01.ptr->save, save);
-	nested_load_control_from_vmcb12(svm, ctl);
 
 	svm_switch_vmcb(svm, &svm->nested.vmcb02);
 	nested_vmcb02_prepare_control(svm);
@@ -1438,6 +1441,9 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
 out_free_save:
 	memset(&svm->nested.save, 0, sizeof(struct vmcb_save_area_cached));
 
+out_free_ctl:
+	memset(&svm->nested.ctl, 0, sizeof(struct vmcb_ctrl_area_cached));
+
 out_free:
 	kfree(save);
 	kfree(ctl);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 169b930322ef..5ec4f56b3b09 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2465,7 +2465,7 @@ static bool check_selective_cr0_intercepted(struct kvm_vcpu *vcpu,
 	bool ret = false;
 
 	if (!is_guest_mode(vcpu) ||
-	    (!(vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_SELECTIVE_CR0))))
+	    (!(vmcb_is_intercept_cached(&svm->nested.ctl, INTERCEPT_SELECTIVE_CR0))))
 		return false;
 
 	cr0 &= ~SVM_CR0_SELECTIVE_MASK;
@@ -4184,7 +4184,7 @@ static int svm_check_intercept(struct kvm_vcpu *vcpu,
 		    info->intercept == x86_intercept_clts)
 			break;
 
-		if (!(vmcb_is_intercept(&svm->nested.ctl,
+		if (!(vmcb_is_intercept_cached(&svm->nested.ctl,
 					INTERCEPT_SELECTIVE_CR0)))
 			break;
 
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index a00be2516cc6..69dbce80b4b8 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -152,7 +152,7 @@ struct svm_nested_state {
 	bool nested_run_pending;
 
 	/* cache for control fields of the guest */
-	struct vmcb_control_area ctl;
+	struct vmcb_ctrl_area_cached ctl;
 	struct vmcb_save_area_cached save;
 
 	bool initialized;
@@ -487,17 +487,17 @@ static inline bool nested_svm_virtualize_tpr(struct kvm_vcpu *vcpu)
 
 static inline bool nested_exit_on_smi(struct vcpu_svm *svm)
 {
-	return vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_SMI);
+	return vmcb_is_intercept_cached(&svm->nested.ctl, INTERCEPT_SMI);
 }
 
 static inline bool nested_exit_on_intr(struct vcpu_svm *svm)
 {
-	return vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_INTR);
+	return vmcb_is_intercept_cached(&svm->nested.ctl, INTERCEPT_INTR);
 }
 
 static inline bool nested_exit_on_nmi(struct vcpu_svm *svm)
 {
-	return vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_NMI);
+	return vmcb_is_intercept_cached(&svm->nested.ctl, INTERCEPT_NMI);
 }
 
 int enter_svm_guest_mode(struct kvm_vcpu *vcpu, u64 vmcb_gpa, struct vmcb *vmcb12);
-- 
2.27.0